This invention, for the first time, tries to develop coupled xcex4-InP channel In0.34Al0.66As0.85Sb0.15/InP heterostructure field-effect transistor (HFET) on InP substrate through metalorganic chemical vapor deposition (MOCVD).
As the transmittal property of InGaAs is better than that of GaAs, it is proved that the performance of InAlAs/InGaAS High Electron Mobility Transistor (HEMT) is superior to that of AlGaAs/GaAs HEMT in terms of high frequency and low noise. However, the higher output conduction and lower avalanche voltage restrict the application of InAlAs/InGaAS HEET in power amplifiers. The two main factors for this are: (1) the energy gap(Eg) of In0.53Ga0.47As is only 0.73eV, only half of GaASxe2x80x2 energy gap of 1.42eV; and (2) The schottky potential energy barrier of In0.52Al0.48As is 0.66ev, lower than that of AlGaAs (leV).
Up to now, there are many documents published concerning methods of improving the avalanche voltage of High Electron Mobility Transistor (HEMT), but all of them have limited effect. The experimental result of In0.34Al0.66As0.85Sb0.15/In0.75Ga0.25As/InP HFET published by inventor (IEEE Electron Device Lett. Vol. EDL-19, pp.195-197, 1998) proves that, comparing with FETs with similar gate length in other documents published, the new design can significantly improve the avalanche voltage on two or three terminals of it. But, using InGaAs as channel layer has inherent defect, i.e. at higher suction-source voltage, there is still the problem of high conduction. In addition, X. Zheng et al.(Appl. Phys. Lett. Vol.62, pp.504-506, and Vol.62, pp.3455-3457, 1993) has proved that, when double xcex4 doping structure has suitable space layer, the electrovalence rate in it will significantly increase due to coupling effect. But so for, relevant studies still concentrates on GaAs-based components.
The main purpose of this invention is to state a coupled xcex4-InP channel In0.34Al0.66As0.85Sb0.15/InP heterostructure field-effect transistor (HFET). Whether gd, is significantly smaller than that of our previously reported InAlAsSb/InGaAs/InP HFET. These characteristics are attributed to the use of the coupled xcex4-doped structure, InP channel, In0.34Al0.66As0.85Sb0.15 Schottky layer"" and to the large conduction-band discontinuity(xcex94Ec) at the InAlAsSb/InP heterojunction.
Another purpose of this invention is to claim a methods for to manufacture the coupled xcex4-InP channel In0.34Al0.66As0.85 Sb0.15/InP heterostructure field-effect transistor (HFET).
The invention will now be described by way of example with reference to the accompanying Tables and Figures in which: certain illustrative embodiments thereof have been shown by way of example in the drawing and will herein be described in detail.